A suggestion has been made to take an image of an area in front of a vehicle with a camera and obtain, based on the taken image, information required to support vehicle operation.
For example, Patent Document 1 discloses an on-board device that extracts information on road signs and other elements from an image taken with an on-board camera and displays the extracted information on a display device. Even in a situation where road sign information stored in a car navigation information storage means includes sign information corresponding to subject vehicle position information obtained by a GPS or any other system, if an appropriate road sign is extracted from the image obtained by the imager, the on-board device displays the extracted road sign on the display device.